The 5" metal box should remain where it is; however, if the seat is moved all the way up closest to the airbag, then a magnetic switch (a 2 inch black plastic box that's wired to the metal box) moves away from a metal plate on the seat rails, which I "presume" disengages the airbag for safety reasons (your head would receive the full impact of the deploying airbag.) When your seat is midway or further back, the sensor rides along the metal plate.
I had lowered my seat 2 inches, removing the seat rails, so I simply zip-tied the small black sensor to a piece of metal under the seat, leaving the large metal box as-is bolted to the floor boards. Since I'm 6.6 and my seat is now permanently in the full back position, there is little risk of my seat belt stretching or body contorting enough to allow my head to impact the steering wheel, so I'm not too worried. Hopefully, I'll never have the opportunity to test it.